Adjustment scale for switches



Fd). 10, 1931. M E, HENNlNG 1,791,896

ADJUSTMENT SCALE FOR SWITCHES Filed NOV. 19, 1929 Jzzzzezioz' Hf, 'd/coizz 562975272235 7:22655 Z? M /zu/fm Y Acad/v y @y di? Patented Feb. 10, 1931 UNITED STATES PATENT OFFICE MALCOLM E. HENNING, Ol' MOINES, IOWA, ASSIGNOR. TO PENN ELECTRIC SWITCH CO., OF DES MOINES, IOWA, A CORPORATION OF IOWA ADJUSTMENT SCALE FOB, SWITCHES Application led November 19, 1928. Serial Io. 408,283.

22. The bracket 22 is supported on a bar 24, j

The object of this invention is to provide in connection with a pressure actuated switch structure a visual indicating means or scale to denote the amount of adjustment required in order to cause the switch mechanismto operate at a given degree of pressure.

A further object of the' invention is to provide improved means for connecting an indicating member to a pressure spring having an adjustable connection with a threaded member carried by the switch housing.

With these and other objects in view my invention consists in the construction, arrangement. and combination of the various parts of my device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, andillustrated in the accompanying drawings, in which:

Figure 1 is a side elevation of a switch structure to which my improved adjustment scale is applied.

Figure 2 is an opposite side elevation with a face plate removed, parts being broken away and other parts being shown in section.

Figure 3 is a detail sectional view on the line 3 3 of Figure 2 illustrating the manner of mounting the indicating member relative to the adjustable arts.

Figure 4 is a etail section of the same parts on the line 4-4 of Figure 1.

Figure 5 is a perspective view of the indieating member detached.

Figure 6 is a detail section showing a modiied form of means for adjusting the tension of the spring.

In the accompanying drawings I have illustrated a switch housing having an integral wall or rim member 10 of substantially rectangular formation. The housing is adapted to be closed at one side by a face plate (not shown) held in place relative to the wall member 10 by means of screws 12. The opposite face-,of the housing is closed in part by a face plate 14 held in place by screws 16 and in part by a wall member 18 formed integrally with the wall or rim member 10.

Within the switch housing is mounted a switch arm 20 which is pivoted to a bracket which preferably is of insulating material.

The switch arm 20 carries contacts 26 and 28 which are movable with the switch arm.

The bar 24 carries contacts 30 and 32 adapted to coact with the contacts 26 and 28 when the switch arm 2O is in closed position shown in Figure 2. The contact 32 is mounted on a plate 34 which also serves the purposev of supporting a permanent magnet 36 relative tothe barv 24. The magnet 36 is adapted to act upon the switch arm 20 for'moving the same when it reaches a predetermined position.

Secured to the housing wall 10 is a bellows housing 38 containing a bellows 40 which is sealed relative to the bellows housing by means of a peripheral flange 42. A threaded nipple 44 is mounted on the bellows housing 38, by means of which pressure from a suitable source may be introduced into the bellows housing around the bellows for acting thereupon.

The bellows 40 is provided with a head 46 to which is secured an operating pin 48. The pin engages a lever and compression of the bellows 40 is opposed by a spring 52 within the switch housing.

The spring 52 is adjustable as to tension and, inthe form shown in Figures 2 and 4, a collar 54 is threaded on a stud 56 carried by the housing wall 10. An adjusting washer 58 is rigidly fixed to the collar 54 and forms a support for one end of the spring 52. A similar adjusting washer 6U acts as a support for the other end of the spring 52 and-.the last named washer is provided with a center pin 62 engaging the lever 50 in opposition to the pin 48. The adjusting washers 58 and preferably are formed with milled or fluted peripheries to facilitate the operation of adjustment by manually engaging them for causing their rotation.` j

The lever arm 50 is part of a bell crank lever having a second arm 6 4 which is operatively connected by means of a link 66 with the switch arm 20. The foregoing descrip'- tion is that of a common switch structure to which my invention may be applied.

This switch structure may also include a lost motion connection between the lever armv 64 and the switch arm 20, including a rod 68v threadedly mounted on the link 66 and having a portion extending through a slot in a tting 72. The rod 68 engages between one thereby regulating the amount of play of the rod 68 in the slot 70. The purpose of this adjustment is for regulating the amount of the differential between the opening and closing of the switch arm 20 and it forms no part of my present invention.

In the operation of the switch mechanism as described, it will be obvious that a varying source of pressure connected with the nipple 44 will cause movement of the bell crank having the arms 50 and 64 for imparting longitudinal movement to the link 66 whereby said rod will move in the slot 70 ofv the fitting 72.

Assuming the switch-arm 20 to be in open position, when suiicient pressure is introduced to the bellowshousing 38, the rod 68 will move relative to the fitting 72 so that it engages the arm 74. Further movementof the rod 68 causes the switch arm 20 to move toward closing position and when the pres- .part of the rod 68 extending within the slot 0, as indicated in Fi ure 2, and the magnet itself performs the nal closing operation. When pressure within the bellows housing 38 is reduced t0 a vpredetermined point, the end of the rod 68 will engage the end of the slot 70 for moving the switch arm to open position. The .magnet 36 will resist such movement, so that as the pressure continues to reduce, the spring 52 will exert extra ten-v sion on the lever arm 50. When this extra tension is suicient to overcome the force of the magnet 36 upon the switch arm 20, the switch arm will be moved toward open position. As soon as it starts such movement it will immediately be in aweaker magnetic field so that the switch opening movement is accelerated and given a sna action.

The spring 52 is provide primarily for thev pur ose of changing therange or setting .of the evice. In other words it determines the degree of pressure at which the switch ing determined by the lost motion connec-` tion including the slot 7 0 and screw 76.

It is also obvious that the, range or point of pressure at which the switch will operate in one direction is determined by the strength of the spring 52 and that this point may be varied by adjusting the tension of said.

spring. This adjustment is effected by turnin the collar 54 and this may be accomplished manually by rotating the washer 58 or indeed by manual rotation of the washer` 60, each of said washers preferably bein rigidly connected to the spring 52.

Assuming that the differential of operation is two pounds, the spring 52 may be adjusted for opening the switch at ten pounds pressure and closing it at twelve pounds pressure, for example. By increasmg the tension of the spring 52, the switch may be opened at twenty pounds pressure and closed at twenty-two pounds pressure, for example. The diierential of operation in each case remains the same, unless an adjustment is made by turning the screw 7 6.

My present improvement relates to a visual means for guiding the operator in adjusting the tension of the screw 52 whereby the required adjustment may be made for causing the switch to operate at a given range or degree of pressure.

A guide plate 80 is providedand it has a swivel connection with the collar 54. The swivel connection may be accomplished by forming the guide plate 80 with' `a key hole slot 82 which loosely engages the collar 54 between the washer 58 and a iange 84 formed on one end of the collar. yBecause of the key hole forma-tion of the slot 82 the operation of' assembling the plate upon collar is facilitated in that the wider end of the slot may be Icaused to pass over the ange 84 and then the plate is slid lengthwise so that the narrow end of the slot engages collar 54 whereby removal of the plate by movementlongltudinally of the axis of. the Collar 1s prevented.

The guide plate 80 is formed at one end with a narrow arm 85 which extends through a longitudinal slot 86 formed in the housing wall 18. j

A scale plate 88 is mounted on the outer face of the wall member 18 and is formed' with a slot 90 registering with the slot 86. The arm 85 'of the guide plate extends also through the slot 90 and is formed at its end with an indicating finger 92 which overlies one margin of the slot 90.

The' scale plate 88 is formed with suitable graduations 94 extending along one margin of the slot 90 to exact with the indicating finger 92 in determining the amount of the desired adjustment. The graduation 94 includes suitable indicia and these may extend v as the collar 54 is rotated on said stud. This ployed for causing an operation of the switch of course causes the indicating finger 92 to travel along the .slot 90 and the marginal graduations 94.

The scale plate 88 may have a slight range of adjustment on the housing wall 18 by means of screws 96 extending through slots 98, so that the scale late may be initially located in the required position for causing the graduations'94 to conform to the tension actually exerted by the spring 52.

It is obvious that my present invention may be ap lied to an type of switch mechanism in w 'ich an a justable spring is emarm in one direction, the spring being adjustableby means of arotary member. lIt is also obvious that any type of switch arm and operating means therefore may be employed in the switch mechanism.

In the form shown in Figure 6 the adjusting means for spring 52 consists of a screw member 100 which takes the place of the stud 56 in the other construction. The screw 100 has a threaded engagement with a tap seat 102 formed in the wall 10 of the housing.

The screw 100 yextends outside of the housing and is formed with a milled head 104 by means of which it ma be rotated manually for adjusting the tenslon of the spring 52.

The inner end portion of the screw 100 has a swivel connection with a collar 106 which corresponds with the threaded collar 54: of the form heretofore described. The collar 106 is formed with end flanges 108 and it supports a washer 110 engaging one end of the spring'52. The collar 106 also carries an indicating plate in a manner similar to that described in connection with the other construction.

In the modied form according to Figure 6, the adjusting plate A travels in a direction axially ofthe spring 52 when the screw 100 is rotated for adjusting the tension of the spring. The indicating finger 92 of the indicating plate acts in a manner previously described to denote the pressure exerted by the spring.

Y It should be noted that the term pressure as used herein is intended to cover means for actuating the switch arm or the like in one direction in opposition to the spring 52 and that this means is so actuated that the sprin switch arm may be employed, as for example, in connection with devices controlled by differences of temperature or pressure or operation of a float device. I have, therefore,

employed the term pressure merely as a convenient way of illustrating a source of power or energy for operating the switch device in one direction and I do not intend to limit myself to the ordinary meaning of the term lwhere it is so used.

It is also obvious that the switch arm may be so set or arrar ed that it operates reversel of the method here illustrated and descri d.

Some changes may be made in the construction and arrangement of the parts of my'device without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims, any modlied forms of structure or use'of mechanical equivalents, which may be reasonably included within their scope.

'I claim as my invention:

1. In a-switch mechanism having a hous-` ing, a switch arm, a lever, a pressure actuating means acting on said lever2 connections between said lever and the swltch arm for actuating the latter in one direction with variation of pressure in said pressure actuating means, and a spring acting on said lever in opposition to said pressure actuating means, rotary means for adjusting the tension of said spring; an adjustment indicator comprising an indicating plate having a swivel connection with the rotary adjustin means, a mrt on said late extending outsi e of the ou'sing, and) a graduated scale carried by the housing to coact with said part for indicating the degree of adjustment of said s ring.

2. n a switch mechanism, a coil spring, a threaded member arranged axiall of said for adjusting the tension of t e latter, a col ar on said threaded member, said collar engaging the spring for forming a support for one end thereof, and being movable in a direction axially of the spring as the tension thereof is adjusted, an indicating plate havin a swivel connection with sald collar, an in 'eating finger on said plate, and a graduated scale arranged to coact with said indicating linger to determine the degree of adjustment of said spring.

3. In a switch mechanism', a coil spring, a washer at each end forming supports for said spring, a stud lfixed axiall of said spring, an adjusting collar aving a threa ed engagement -with said stud and rigidl connected with one of said washers, an in icating plate mounted parallel with the last named washer and having an opening to receive said collar, means for holding said indicating plate in fixed relation to said collar and the adjacent washer to cause travel of said plate longitudinally of the stud as said -130 collar is rmzated,` without correspon turnin of the' 1ste, and means coactmgwi said p ate for indicating the amount of adjustment vof said spring by rotation' of said collar.

- 4. In a switch mechanism, a housing, a coil spring in said housing, a washer at each end forming supports for said sprin a stud xed axial y of said spring, an a' justin collar having a threaded enga ment wit said. stud and rigidly connecte' with one of said washers, an indcatin plate mounted parallel with the last name washer and having an opening to receive said adjusting co1- lar, means for holding said indicatin plate in fixed relation to said collar and t ead- 'acent washer to causetravel of said plate ongitudinally of the stud as said collai` is rotated, said housin being formed with a slot, an arm on sai indicating plate projectmg through saidslot and formed vat its end with a pointer, and a graduated scale arranged alon one mar 'n of-said slot to coact with sai pointer 1n determining the adjustment of said spring.v

Des Moines Iowa Se tember 18 1929.

MALCL E. HENNING. 

